Low-water alarm.



No. 792,257. PATENTED JUNE 13, 1905. .A. E. GARDNER.

LOW WATER ALARM.

APPLICATION mum In. 17, 1905.

UNITED STATES Patented June 13, 1905.

PATENT OFFICE.

ADDISON E. GARDNER, OF MILAN, MICHIGAN, ASSIGNOR TO GEORGE IV KENNEDY, -OE JACKSON, MICHIGAN.

LOW-WATER ALARM.

SPECIFICATION forming part of Letters Patent No. 792,257, dated June 13, 1905.

Application filed March 17,1905. Serial Nov 250,665.

, To (tZZ whom it may concern.-

Be it known that I, ADDISON E. GARDNER, a citizen of the United States, residing at Milan, in the county of 'ashtenaw and State of Michi- 5 gan, have invented certain new and useful Improvements in Low-\Vater Alarms, of which the following is a specification, reference being had therein to the accompanying drawings.

I The invention relates generally to low-water alarms, and particularly to an alarm of this type having an expansible member adapted to close an electric circuit automatically to sound the alarm when the level of the water 5 in the boiler reaches a predetermined point.

It is the object of the present invention to produce an alarm of the character referred to in which the contact member forming part of the circuit-closure will be returned under all conditions after operation by the thermostat to its normal position, thus insuring the effective operation of the alarm.

\Vith this object in view the invention consists in the peculiar construction of the lowwater alarm and, further, in the novel arrangement and combination of its parts, as will be hereinafter more fully set forth.

In the drawings, Figure 1 is a view in elevation of my improved alarm. Fig. 2 is plan 0 view of the contact member forming part of the circuit-closure, and Fig. 3 is an end view of the upper portion of the alarm.

A represents the expansible member, consisting in this instance of a tube having at 3 5 one end the nipple B, adapted to be attached to the boiler B and to communicate with the interior thereof and provided at its opposite end with a cap (I.

D represents a non-expansible rod having 40 a threaded extension (Z, adjustably engaging an apertured ear (1 on the coupling B and held in its proper adjusted position by the nuts II".

E represents a lever fulcrumed to the upper end of the rod D, as plainly indicated in Fig. 1, and pivoted to the cap O between spaced uprights a. The lever projects, as shown, some considerable distance beyond the tube and carries at its free end a sleeve 7),

threaded interiorly, and a screw 0 within the 5 sleeve, which extends beyond the upper end of the latter, forming a contact-point J.

L designates an extension upon the cap O, upon the top of which is secured a flexible member M, in this instance in the form of a leaf-spring extending above and in parallelism with the lever, as shown. Above the spring and also secured to the extension L is a rigid arm N, carrying a screw O, by means of which the flexible member is adjusted. At the end and upon the under face of the spring member is secured a socket 0, and immediately thereabove upon the spring-top is mounted a collarf.

7 is a contact in the form of a plug sur- 5 rounded by an insulating-bushing g, which is fitted within the collar over the socket and is held in place by the set-screw la. The plug projects upwardly beyond the collar and insulating material and is provided with a suit- 7 able thumb-nut '1', forming one of the terminals of the electric circuit. The other terminal consists of a post H upon the extension L.

Q designates a suitable battery, R any desired form of signal or alarm, in this instance a bell, and R a circuit connecting the terminals and including the contacts upon the spring member and lever.

S is any ordinary blow-off cock for the 0 pipe A.

In operation the contacts are first properly adjusted, so that upon the expansion of the tube the circuit will be closed automatically and the alarm sounded. The contacts are nor- 8 5 mally separated; but when the water in the boiler drops to the danger-point steam enters the tube, causing the latter to expand. The lever is rocked thereby and its contact-point moved upwardly into engagement with the contact upon the spring member, thereby closing the circuit and sounding the alarm. Upon the cooling of the expansible member the lever is drawn positively back into its initial position, and the spring member carrying the complementary contact-point also returns to its initial position, (due to its flexibility,)even though it may have been flexed by the lever through the expansion of the tube to an abnormal extent. Thus it will be obvious that after having once adjusted the contacts further adjustment will not be necessary and the user will be assured of the eflicient operation of the device under all conditions.

What I claim as my invention is 1. In a low-water alarm, the combination, with a tubular expansible member, of an ad joining non-expansible member, a lever fulcrumed upon said latter member and having a pivotal connection with theexpansible member, a contact-point carried by the lever, a flexible member carrying a contact-point in operative relation to the lever-contact, and an electrical circuit including said contacts and a signal.

2. In a low-water alarm the combination, with a tubular expansible member, of an adjoining non-expansible member, a lever fulcrumed upon said latter member and having a pivotal connection with the expansible member, a contact-point carried by the lever, a flexible member carrying a contact-point in operative relation to the lever-contact, means for adjusting the flexible member, and an electrical circuit including the contacts and an alarm.

3. In a low-water alarm, the combination of two parallelly-arranged members, one expan- 3 sible and tubular and the other non-expansible, a lever fulcrumed upon one end of the non-expansible member and pivoted to the immediately-adjacent end of the tubular member, adjustable connections between the oppo- 55 site ends of said members, a flexible member supported upon the tube above and in parallelism with the lever, alining contacts carried by said lever and flexible member, and an electrical circuit including the contactsand a 4 signal.

4. In a low-water alarm, the combination, with an expansible and a non-expansible member adj ustably connected to two of their ends,

of a lever pivotally connected at one end to 45 the opposite ends of the members, an ad justable contact-point carried by said lever at its extremity, a flexible member attached to said expansible member and carrying an insulated contact-point in operative relation to the le- 5 

